Heat Exchanger, in Particular a Charge Intercooler or Coolant Cooler for Motor Vehicles

ABSTRACT

The invention relates to a heat exchanger ( 1 ), in particular a charge intercooler or coolant cooler for motor vehicles, which comprises a soldered block which is made of pipes ( 4 ), ribs and at least one pipe base ( 2 ), in addition to at least one plastic box ( 3 ) which has a wall ( 3   a ) which extends in the cross-section and which is approximately U shaped and a surrounding flange ( 3   b ). The box is mechanically connected to the pipe base over flange ( 3   b ). According to the disclosure, reinforcing ribs are arranged on the inner side of the plastic box ( 3 ) in a transition area between the flange ( 3   b ) and the wall ( 3   a ).

The invention relates to a heat exchanger, particularly a charge intercooler or coolant cooler for motor vehicles according to the preamble of claim 1.

Known heat exchangers, particularly for motor vehicles, frequently have a soldered block, consisting of pipes, ribs as well as pipe bases, on which collection boxes made of plastic are attached. The connection between the plastic boxes and the pipe base is designed as a clamp or crimp connection, where a seal is inserted between a flange of the plastic box and the pipe base and clamped by the box/base connection. As a result, the plastic boxes are connected firmly and sealingly to the metallic pipe base.

Such a box/base connection has become known from DE-B 28 52 408 of the applicant, where deformable marginal areas of a pipe base engage via a flange of a water box, and thus establish a positive-lock connection. If the internal pressure is increased, the plastic boxes tend to be exposed to deformations and elevated stresses, particularly above the clamping area, which can also lead to leaks of the box/base connection.

In DE-A 6b 38 41 470 of the applicant, a modified flange area has therefore been proposed for so-called wavy slot crimping, wherein the wall of the box is designed to be wavy above the flange, and thus the longitudinal wall is stiffened.

In charge intercoolers, such as those disclosed in DE-A 198 57 435, higher internal pressures occur particularly inside the plastic box, and the trend is towards increased pressures in future developments, so that conventional plastic boxes are unable to withstand the stress. Rather, deformations can occur, which result in increased stresses and crack formation.

The problem of the invention is to improve a heat exchanger of the type mentioned in the introduction, particularly its plastic box with regard to resistance to internal pressure, without at the same time substantially increasing the weight of the heat exchanger.

This problem is solved by the characteristics of claim 1. According to the invention, a plurality of reinforcing ribs is provided on the interior side of the plastic box above the flange, i.e., in the transitional area between the flange and the box wall. As a result, the advantage is achieved that the plastic box, in case of increased internal pressure, is reinforced in the critical area and becomes more resistant to deformations. Thus, in this area of the box, above the box/base connections, stress peaks are reduced to a permissible value. In particular, a plastic box that has been reinforced according to the invention can be used as a charge intercooler.

In an advantageous embodiment of the invention, the plastic box has a U-shaped cross-sectional profile, which due to an offset becomes the circumferential flange. In the corner area of the offset, which is designed with a substantially obtuse angle, the reinforcing ribs are arranged on the interior side, and their inner edges are preferably aligned with a U profile of the interior wall of the box. As a result, the advantage is achieved that the reinforcing ribs are arranged in an area where they do not pose any noteworthy flow resistance against the medium, that is the coolant or charge air which flows through the box, i.e., the reinforcing ribs according to the invention do not produce an increased pressure drop in the plastic box. They also do not produce a noteworthy weight increase, because the wall thickness of the box itself is not increased, and the ribs are formed with relatively thin walls. Thus, they increase the section modulus in the critical area of the box, in a relatively weight-neutral way and without pressure loss, where the box is stressed particularly due to bending as a consequence of the increased internal pressure at this place.

In an advantageous variant of the invention, the heat exchanger has a block with a single row or multiple row flat pipe system, where the ends of the flat pipes are received in through holes in the pipe base. The reinforcing ribs have a separation from each other, which corresponds to the pipe spacing, i.e., the separation of the pipes, or to an external rib spacing, i.e., the separation of ribs on the external side of the box. Here, the reinforcing ribs can be arranged either at the height of the pipes or between them. The result is an even reinforcement of the longitudinal wall of the box which is adapted to the internal pressure load.

In another advantageous embodiment of the invention, the transitional area between the flange and the box wall has a wavy design in the longitudinal direction of the box, as is already known from DE-A 38 41 470 of the applicant that was mentioned in the introduction. The reinforcing ribs are arranged advantageously in the area of this wave profile, in the area of recesses (wave troughs) or the bulges (wave crests) on the interior side of the box. As a result, the advantage achieved is that of an additional reinforcement without a noteworthy increase in the pressure loss in the box.

In another advantageous embodiment of the invention, the rib surfaces, which protrude into the interior of the plastic box, are arranged parallel to the mold removal direction of the box. Thus, the rib profiles can be incorporated into the core of the box, which is removed, after completion of injection molding of the box, in the demolding direction without the use of additional core slides, i.e., they can be removed from the mold. As a result, the advantage of lower manufacturing costs is achieved since no substantial increase in the cost of the injection tool is associated with the design and arrangement of the reinforcing ribs according to the invention.

An embodiment example of the invention is represented in the drawing and explained in greater detail below. In the drawing

FIG. 1 shows a section of a heat exchanger according to the invention with connection between the pipe base and the plastic box,

FIG. 2 is an oblique X of FIG. 1 with reinforcing ribs according to the invention,

FIG. 3 is an oblique representation of the plastic box with a first arrangement of reinforcing ribs,

FIG. 4 shows the plastic box with a second arrangement of reinforcing ribs,

FIG. 5 shows a section of the longitudinal wall of the plastic box (first arrangement),

FIG. 6 shows a cross section along the line VI-VI in FIG. 5,

FIG. 7 shows a section of the longitudinal wall of the plastic box (second arrangement), and

FIG. 8 shows a cross section along the line VIII-VIII in FIG. 7.

FIG. 1 shows a cross section of a heat exchanger 1 according to the invention, which has a pipe base 2, a plastic box 3, and flat pipes 4, which are received in through holes 2 a of the pipe base 2. The pipe base 2 has—as known in the state of the art—an external circumferential channel 2 b, which is followed by an external marginal area 2 c. The plastic box 3 has a U-profile, incompletely shown, with a wall 3 a that becomes a flange 3 b with a larger wall thickness. The flange 3 b as well as a seal—not shown—are inserted in the channel 2 b of the bottom pipe 2 and clamped by the deformable marginal area 2 c by means of a crimping or clamping connection, which is not shown in further detail, against the pipe base 2. Such box/base connections are known from the state of the art, which was mentioned in the introduction, for example, from DE-A 38 41 470. The flat pipes 4 are soldered to the wavy ribs—not shown—and the through holes of the pipe bases, of which only the pipe base 2 is partially visible, to a block. The plastic boxes, of which again only box 3 is shown partially, are placed and clamped on the soldered block.

FIG. 2 shows a section X of FIG. 1, i.e., a transitional area 5 between the wall 3 a of the plastic box 3 and the flange 3 b, where the transition 5 is designed as an offset, and the inner edge 3 d of the wall 3 a is offset towards the interior by approximately one wall thickness compared with the inner edge 3 e of the flange 3 b. Because of the offset 5, the plastic box 3 is thus subjected to so-called drawing in. Arranged in the area of the offset 5, on the interior side of the box 3, are reinforcing ribs 6 whose inner edges 6 a are aligned with the inner edge 3 d of the box wall 3 a. The reinforcing ribs 6 thus fill the obtuse angle of the offset 5 and reach into the area of the flange 3 b. As a result of the arrangement of the reinforcing ribs 6, a reinforcement of the box in the transitional area 5 is achieved, i.e., in an area which is subjected to an increased stress due to the internal pressure. The heat exchanger 1 is designed advantageously as a charge intercooler and therefore receives compressed charge air at approximately 2 bar (higher pressures are to be expected in the future), which leads to a critical stress in the plastic box in the area above the flange; however, the reinforcing ribs according to the invention oppose this stress without increasing the wall thickness, i.e., also without significant weight increase of the box 3.

FIG. 3 is an oblique representation of the corner area of a plastic box 7 with reinforcing ribs 8 according to the invention on the interior side of a longitudinal wall 7 b. The box 7 has a rectangular circumferential flange 7 a, which is not shown in its entirety, and above which a transitional area 9 is arranged that has a wavy design and is known from DE-A 38 41 470 of the applicant, which was mentioned in the introduction; consequently, the latter Offenlegungsschrift is therefore included in its entirety in the disclosure content of this application. The connection—not shown—between the pipe base and the box 7 corresponds to the known embodiment in this Offenlegungsschrift. Due to the wavy design of the transitional area 9, recesses 10 and bulges 11 are formed on the interior side of the box 7. In this first embodiment, the reinforcing ribs 8 are arranged above the recesses 10.

FIG. 4 shows a second embodiment for the arrangement of reinforcing ribs 12 in a plastic box 13, which also has a wavy transitional area 9, corresponding to the above described transitional area 9 in FIG. 3. Therefore, on the interior side of the box 13, recesses 10 and bulges 11 are also formed, constituting the wavy wall profile. The reinforcing ribs 12 are arranged here in the area of the bulges 11, i.e., on the raised areas of the interior wall of the box and in each case, between two recesses 10. To that extent, the length of the reinforcing ribs 12 is here greater than in the embodiment example according to FIG. 3. In both embodiment examples, i.e., in the reinforcing ribs 8 and the reinforcing ribs 11, the rib surfaces (corresponding to the surface 6 in FIG. 2) are in each case parallel to each other, where these surfaces are approximately perpendicular to an imaginary pipe base plane, or to a plane spanned by the circumferential flange 7 a. This means that a core—not shown—an be removed in a direction, the so-called mold removal direction, during manufacture of the plastic boxes 3, 7, 13. The arrangement and design of the reinforcing ribs 6, 8, 12 thus does not require an additional core slide, and it can also be carried out by modifying an existing tool.

FIG. 5 shows another representation of the embodiment according to FIG. 3, i.e., a view of a section of the longitudinal wall 7 b of the plastic box 7 with the flange 7 a. Above the flange 7 a, the wavy transitional area 9 is suggested. The longitudinal wall 7 b is reinforced on its external side by a transverse rib 7 c.

FIG. 6 shows a cross section along the line VI-VI in FIG. 5, i.e., through the flange 7 a. On the internal side of the longitudinal wall 7 b, recesses 10 and bulges 11, that is wave crests and wave troughs, are formed in the area of the wave profile 9 (see FIG. 5). In each case the reinforcing ribs 8, which protrude vertically into the interior, are arranged between two bulges 11, i.e.,—as can be seen in FIG. 3—above the recesses 10. The reinforcing ribs 8 extend towards the interior up to a line 7 d, which forms the inner contour of the longitudinal wall 7 b. In this respect, the reinforcing ribs 8 are aligned with the interior wall 7 d, which ensures a small pressure drop. The separation of the reinforcing ribs 10, moreover, corresponds to the separation of the flat pipes—not shown. The ribs 8 also extend at right angles to the plane of the drawing and can thus be easily removed from the mold with the main core of the box.

FIG. 7 shows a view of a section of the side wall 13 a (see FIG. 4) of the box 13 with the wave profile 9.

FIG. 8 shows a cross section along the line VIII-VIII in FIG. 7 through the flange of the box 13. As a result of the wave profile 9, the recesses 10 and the bulges 11, on which the reinforcing ribs 12 (see FIG. 4) are arranged, are formed on the interior side. The reinforcing ribs 12 which extend perpendicularly towards the interior extend up to an edge 13 b, which corresponds to the inner edge of the longitudinal wall 13 a (perpendicular to the plane of the drawing). Thus, the reinforcing ribs 12 do not extend farther into the interior space of the box than the longitudinal wall 13 a itself, and thus they also do not produce an increased pressure drop for the flow medium, for example, charge air or coolant. 

1-10. (canceled)
 11. A heat exchanger, particularly a charge intercooler or coolant cooler for motor vehicles, with a specially soldered block consisting of pipes (4), ribs and at least one pipe base (2), as well as at least one box (3), particularly one made of plastic or metal, which has a wall (3 a), particularly one with an approximately U-shaped cross section, and a circumferential flange (3 b), and which is connected mechanically via the flange (3 b) to the pipe base (2), characterized in that, on the internal side of the box (3), particularly in a transitional area (5), reinforcing ribs (6) are arranged between the flange (3 b) and the wall (3 a).
 12. The heat exchanger according to claim 11, characterized in that the transitional area has an offset (5) which is directed inward and in particular is peripheral.
 13. The heat exchanger according to claim 11, characterized in that the reinforcing ribs (6) have inner edges (6 a) that are designed to be in alignment with the internal wall (3 d).
 14. The heat exchanger according to claim 11, characterized in that the pipes are designed as round, oval or flat pipes (4), arranged in one or more rows, and received in the at least one pipe base (2), and in that the reinforcing ribs (6) are arranged on the walls (3 a) of the plastic box (3) with separations that correspond to the pipe spacing or to an external rib spacing.
 15. The heat exchanger according to claim 14, characterized in that the reinforcing ribs (6) are arranged in each case at the height of the pipes (4).
 16. The heat exchanger according to claim 14, characterized in that the reinforcing ribs (6) are arranged in each case between the pipes (4).
 17. The heat exchanger according to claim 11, characterized in that a transitional area (9) is included as part of te construction, said transitional area (9) having a wavy design and exhibits recesses (10) as well as bulges (11) on the interior side, and recessed areas on the external side of the plastic box (7, 13) in which parts of the pipe base engage with positive locking.
 18. The heat exchanger according to claim 17, characterized in that reinforcement ribs (8) are arranged above the recesses (10).
 19. The heat exchanger according to claim 17, characterized in that other reinforcing ribs (12) are arranged in the area of the bulges (11) and between the recesses (10).
 20. The heat exchanger according to claim 11, characterized in that the reinforcing ribs (6) have rib surfaces that are arranged parallel to the direction of removal of the box (3) from a mold.
 21. The heat exchanger according to claim 17, characterized in that the reinforcement ribs (8) have rib surfaces that are arranged parallel to the direction of removal of the box (7) from a mold.
 22. The heat exchanger according to claim 19, characterized in that the other reinforcing ribs (12) have rib surfaces that are arranged parallel to the direction of removal of the box (13) from a mold. 